Mapping of the phosphorylation sites on the phototropic signal transducer, NPH3

Tsuchida-Mayama, Tomoko; Nakano, Michiharu; Uehara, Yukiko; Sano, Miho; Fujisawa, Noriko; Okada, Kiyotaka; Sakai, Tatsuya

doi:10.1016/j.plantsci.2008.03.018

Cited by 45 publications

(85 citation statements)

References 27 publications

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“…effects of the rpt2 mutation on the blue light-induced dephosphorylation of NPH3 proteins by observing the alteration of molecular weights of NPH3 proteins in an immunoblot analysis (Figure 8), as reported previously (Pedmale and Liscum, 2007;Tsuchida-Mayama et al, 2008). Most NPH3 proteins extracted from dark-grown seedlings were found in a crude microsomal membrane fraction, indicating that NPH3 proteins are localized mainly to plasma membranes under dark conditions ( Figures 8A and 8B), as reported previously (Motchoulski and Liscum, 1999).…”

Section: Dephosphorylation Of Nph3 Proteins Is Mediated By Rpt2supporting

confidence: 84%

“…When wild-type seedlings were irradiated with unilateral blue light at a very low fluence rate (0.0017 mmol m -2 s -1 ), we observed three types of NPH3 proteins with different mobility, presumably reflecting variations in the dephosphorylation status of NPH3 proteins (slightly, moderately, and excessively dephosphorylated) ( Figure 8A). Those distinct bands of NPH3 proteins were not detected in previous studies (Motchoulski and Liscum, 1999;Pedmale and Liscum, 2007;Tsuchida-Mayama et al, 2008). A preparation of the microsomal membrane fraction enhanced the detection of bands of different molecular weights.…”

Section: Dephosphorylation Of Nph3 Proteins Is Mediated By Rpt2mentioning

confidence: 60%

“…phosphatase inhibitors simultaneously suppresses NPH3 dephosphorylation and phototropic responses. However, we have already indicated that NPH3 dephosphorylation is unnecessary, at least for the phot2-induced phototropic response, and that the effects of such phosphatase inhibitors is questionable because they also affect other signaling mechanisms to induce hypocotyl tropism downstream of NPH3 (Tsuchida-Mayama et al, 2008). This study suggests that nonphosphorylated NPH3 is an inactive form that cannot transduce phot signals to induce phototropic responses, because excessively dephosphorylated NPH3 proteins and suppression of phototropic responses appear together.…”

Section: Discussionmentioning

confidence: 78%

“…Blue light-induced autophosphorylation of phot proteins (Christie et al, 1998;Sakai et al, 2001) and the dephosphorylation of NPH3 proteins (Motchoulski and Liscum, 1999;Pedmale and Liscum, 2007;Tsuchida-Mayama et al, 2008) are the early events of phot signaling involved in phototropic responses. Pedmale and Liscum (2007) proposed that NPH3 dephosphorylation is a trigger response for phototropic responses, because phot1 activation causes its dephosphorylation and treatment with protein Phosphorylated NPH3 proteins interact with phot1 proteins under darkness.…”

Section: Discussionmentioning

confidence: 99%

“…A defect in NPH3 causes a complete loss of phototropism in Arabidopsis and rice (Oryza sativa) seedlings (Motchoulski and Liscum, 1999;Haga et al, 2005). NPH3 is phosphorylated under dark conditions and dephosphorylated by blue light irradiation in a phot1-dependent manner (Pedmale and Liscum, 2007;Tsuchida-Mayama et al, 2008). It appears that phototropic responses depend on dephosphorylation of NPH3 and that NPH3 is active when dephosphorylated (Pedmale and Liscum, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

et al. 2015

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Living organisms adapt to changing light environments via mechanisms that enhance photosensitivity under darkness and attenuate photosensitivity under bright light conditions. In hypocotyl phototropism, phototropin1 (phot1) blue light photoreceptors mediate both the pulse light-induced, first positive phototropism and the continuous light-induced, second positive phototropism, suggesting the existence of a mechanism that alters their photosensitivity. Here, we show that light induction of ROOT PHOTOTROPISM2 (RPT2) underlies photosensory adaptation in hypocotyl phototropism of Arabidopsis thaliana. rpt2 loss-offunction mutants exhibited increased photosensitivity to very low fluence blue light but were insensitive to low fluence blue light. Expression of RPT2 prior to phototropic stimulation in etiolated seedlings reduced photosensitivity during first positive phototropism and accelerated second positive phototropism. Our microscopy and biochemical analyses indicated that blue light irradiation causes dephosphorylation of NONPHOTOTROPIC HYPOCOTYL3 (NPH3) proteins and mediates their release from the plasma membrane. These phenomena correlate closely with the desensitization of phot1 signaling during the transition period from first positive phototropism to second positive phototropism. RPT2 modulated the phosphorylation of NPH3 and promoted reconstruction of the phot1-NPH3 complex on the plasma membrane. We conclude that photosensitivity is increased in the absence of RPT2 and that this results in the desensitization of phot1. Light-mediated induction of RPT2 then reduces the photosensitivity of phot1, which is required for second positive phototropism under bright light conditions.

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Section: Dephosphorylation Of Nph3 Proteins Is Mediated By Rpt2supporting

confidence: 84%

Section: Dephosphorylation Of Nph3 Proteins Is Mediated By Rpt2mentioning

confidence: 60%

Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

et al. 2015

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Signaling in Phototropism

Celaya

Pedmale

Liscum

2009

Signaling and Communication in Plants

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Light Sensing at the Plasma Membrane

Christie

Kaiserli

Sullivan

2010

The Plant Plasma Membrane

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Light is one of the most important environmental factors controlling plant development and its perception is achieved through a suite of photoreceptor proteins. Like photoreceptors associated with our vision, plant photosensors can detect the presence, intensity, direction and color of light, and in turn, utilize this information to direct their growth accordingly. To date, four different types of photoreceptors have been identified in plants, namely the phytochromes, cryptochromes, phototropins and members of the Zeitlupe (ZTL) family. Phytochromes are photoreversible red/far-red photoreceptors whereas cryptochromes, phototropins and members of the ZTL family specifically absorb UV-A/blue wavelengths. Plants also respond to UV-B and green light, but the photosensors responsible for their detection remain elusive. A summary of light-regulated events that are known to occur at the plant plasma membrane will be discussed, as will the biochemical and photochemical properties of the photoreceptor proteins involved.

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Mapping of the phosphorylation sites on the phototropic signal transducer, NPH3

Cited by 45 publications

References 27 publications

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

Signaling in Phototropism

Light Sensing at the Plasma Membrane

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